The purpose of this project is to study the active site and the mechanism of action of hen egg white lysozyme and of related enzymes. The lysozyme-catalyzed hydrolysis and transglycosylation reactions of the bacterial cell wall oligosaccharides will be investigated under a variety of conditions, as will the effect of different substrates and inhibitors on the optical properties of the enzyme. In addition, affinity labeling reagents will be used to probe the amino acid residues at the active site of the various lysozymes. It is hoped that these studies will (a) lead to a better understanding of the role of functional groups, strains, conformation changes and other factors believed to be responsible for lysozyme catalysis, and thus contribute to the general problem of the relationship between structure and function in proteins; (b) provide information on the comparative biochemistry of lysozymes from different sources; and (c) give a clue to the role of lysozyme and lysozyme-like enzymes in nature, in particular in the process of bacterial cell wall biosynthesis and in certain diseases, such as human leukemia, which results in the secretion of large amounts of lysozyme.